RU2811858C1 - Method of fire protection of process furnaces and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: improvement of steam and gas curtains and the means ensuring fire safety of process furnaces of oil and gas refining and petrochemical plants; namely – a method of fire protection of process furnaces and a device for its implementation. The method of fire protection of process furnaces involves creating a protective curtain of a process furnace by supplying a fire extinguishing agent into a horizontal perforated manifold of the outer protective curtain of the furnace, while a mixture of steam and nitrogen is used as a fire extinguishing agent, while creating a steam and gas curtain, and a homogeneous steam and gas mixture, preparation of which is carried out in Venturi gas mixer (5), is supplied into manifold (1) of the curtain, while, in order to avoid condensation of steam and obtain a homogeneous steam and gas mixture, nitrogen is preheated in heat exchanger (4) to a temperature corresponding to steam temperature, and regulation of the parameters of the resulting steam and gas mixture and control of the operation of the protective steam and gas curtain is carried out automatically by a controller.

EFFECT: improved efficiency and improved steam curtains through producing a homogeneous steam and gas mixture capable of creating a dense protective curtain around the perimeter of the process furnaces.

5 cl, 2 dwg

Description

The group of inventions relates to means ensuring fire safety of technological furnaces of oil and gas refining and petrochemical plants, and concerns the improvement of steam and gas curtains.

Methods and devices are known from the state of the art for fire protection of process equipment and protection of operating personnel from toxic substances associated with fire.

There is a known method of forming a gas-air curtain to protect the population from toxic and toxic substances, which consists in the formation of a ground-level flat free-convective turbulent upward-directed gas-air jet by heating the ground layer of air with a linear heat source placed on the soil surface across the incoming air flow containing toxic or toxic substances (Patent RF No. 2229908 C1, priority date 12/10/2002, publication date 06/10/2004, authors: Obukhov I.A. et al., RU).

A device for forming a gas-air curtain to protect the population from hazardous chemical substances is also known, made in the form of a ground-level linear source of heat released during the combustion of natural gas, containing a horizontal tubular gas manifold with a perforated upper part, mounted on a solid support (RF Patent No. 2255780 C1, priority date 08/05/2004, publication date 07/10/2007, authors: Mayorov V.A., Obukhov I.A. et al., RU).

The disadvantages of the known analogues are: firstly, the low level of fire safety of the method, due to the need to use a linear heat source generated by the combustion of natural gas; secondly, the low productivity of the gas-air curtain due to the formation of the motivating force of the gas-air flow due to convection forces.

In addition, a fire-fighting steam curtain is known, designed to prevent contact of flammable gas mixtures formed during accidents at petrochemical and gas industry enterprises with ignition sources, for example heating furnaces (www.google.com/search?q=steam+curtain+furnaces, date of viewing 02/09/2023).

The disadvantages of this analogue are high energy consumption, which characterizes the energy-intensive approach to the safety of furnaces using steam curtains and their insufficient efficiency, since the steam curtain will perform its protective function only if its response time is less than the time of migration of a fire hazardous or explosive cloud from the location release to the furnace or if the likelihood of igniting the cloud by other random ignition sources is low. At the same time, ensuring the safety of furnaces requires a large consumption of steam and, accordingly, its production, since the supply of steam to the curtains must be in sufficient volumes. (https://chemtech.ru/mozhet-li-parovaja-zavesa-pechej-vypolnit-svoju-zashhitnuju-funkciju/, accessed 02/09/2023).

The closest to the invention is a known device that provides the implementation of a method of gas protection of fire heating furnaces, which are accepted as prototypes of a device and method of gas protection of furnaces, based on the use of nitrogen as a fire extinguishing agent, the creation of an external nitrogen curtain and the use of means for external and internal fire extinguishing . In this case, the device contains a horizontal perforated manifold of an external nitrogen curtain, a distribution pipeline for supplying nitrogen, an internal gas extinguishing pipeline, measuring sensors for the temperature of the furnace flue gases and oxygen concentration and shut-off and control valves (RF Patent No. 55604 U1, priority date 03/16/2006, publication date 08/27/2006, authors: Bessonny A.N. et al., RU, prototype).

The disadvantages of the prototype are: firstly, the likelihood of a significant decrease in the efficiency of the gas curtain as a result of its long-term operation and depletion of nitrogen reserves in the receivers due to prolonged emergency operation of equipment near process furnaces; secondly, insufficient reliability and failure-free operation of the gas curtain, due to the lack of redundancy in the gas protection system.

The technical problem solved by the inventions is to increase the reliability and efficiency of protective steam and gas curtains of technological furnaces of oil and gas refining and petrochemical plants through the combined use of water vapor and gas, in particular nitrogen, in the curtains, as well as automatic control of the parameters of the resulting vapor-gas mixture.

To solve a technical problem, a method for fire protection of technological furnaces has been proposed, which includes creating a protective curtain for the technological furnace by supplying a fire extinguishing agent to the horizontal perforated manifold of the outer protective curtain of the furnace. What is new is that a mixture of water vapor and nitrogen is used as a fire extinguishing agent, while a vapor-gas curtain is created, and a homogeneous vapor-gas mixture is supplied to the curtain collector, the preparation of which is carried out in a gas mixer with the Venturi effect, in order to avoid condensation of water vapor and obtain homogeneous vapor-gas mixture, nitrogen is preheated in a heat exchanger to a temperature corresponding to the temperature of water vapor, and the parameters of the resulting vapor-gas mixture are regulated and the operation of the protective vapor-gas curtain is controlled automatically by a control controller.

According to the invention, the thermal energy necessary for operating the heat exchanger and heating the nitrogen is taken from process furnaces or a steam boiler room of the enterprise or obtained through the use of electric heat exchangers.

To solve the technical problem, a fire protection device for technological furnaces is proposed, containing a horizontal perforated manifold of the outer protective curtain of the technological furnace, pipelines for supplying a fire extinguishing agent to the manifold, shut-off and control valves, and devices for monitoring the operating parameters of the protective curtain. What is new is that the device is made with the possibility of using water steam, as well as a mixture of steam and nitrogen as a fire extinguishing agent, while the device contains a steam supply line to the protective curtain with a measuring sensor-flow meter, and a nitrogen supply line in which a heat exchanger is installed , both lines are combined by a gas mixer with the Venturi effect, while the specified gas mixer is connected by a pipeline to the collector of the protective curtain and the gas pipeline is connected to a heat exchanger installed in the nitrogen supply line, designed to heat the nitrogen to a temperature corresponding to the temperature of water vapor to prevent condensation of water vapor and obtaining a homogeneous vapor-gas mixture in a gas mixer, and the shut-off and control valves installed in these lines, controlled by an electric motor, a heat exchanger and a measuring sensor-flow meter, made with the ability to determine the temperature and actual steam supply, are electrically connected to a software and hardware complex - a controller for automatic control the operation of the protective curtain.

According to the invention, the device contains a steam-coolant supply line connected to a heat exchanger and equipped with valves installed in it, controlled by electric motors and electrically connected to the controller.

According to the invention, the heat exchanger in the nitrogen supply line is electric.

The essence of the invention is illustrated by drawings.

In fig. 1 shows a functional diagram of a device designed to implement a method of fire protection of technological furnaces using a heat exchanger operating from a coolant steam supply line connected to it; in fig. Figure 2 shows an alternative device diagram that uses an electrically heated heat exchanger.

The drawings show the following designations:

1 - protective curtain collector;

2 - steam supply line to the protective curtain;

3 - nitrogen supply line;

4 - heat exchanger;

5 - gas mixer;

6 - connecting pipeline;

7 - tee-distributor;

8 - measuring sensor-flow meter;

9 - line for supplying coolant steam to heat exchanger 4;

10, 11, 12 - shut-off valves;

13, 14 - automatic control valves controlled by an electric motor;

15, 16 - check valves;

17 - software and hardware complex - controller.

Fire protection of technological furnaces by creating vapor-gas curtains is carried out as follows.

If there is a threat of an emergency, for example, a leak of an explosive gas-air mixture on the territory of an oil and gas refining or petrochemical production, steam is supplied to the collectors 1 of all steam curtains by sequentially automatically turning on valves 10, 11 and 12. The measuring sensor 8 determines the temperature and the actual supply of steam coming from the boiler room through the steam line of supply line 2 to the collector 1 of the protective steam curtain, and in case of insufficient performance, it supplies an analog signal to the controller 17 for controlling the operation of the steam curtain. The controller 17, in turn, controls the electric drive of the automatic control valves 13 and 14 to additionally turn on the gas, for example nitrogen line 3 and coolant supply line 9 (Fig. 1). Moreover, the intensity of the nitrogen gas supply is regulated by valve 13 and is determined depending on the lack of steam in line 2 of the steam curtain. Valve 14 regulates the supply of coolant to the heat exchanger 4 to regulate the temperature of the heated nitrogen gas. To obtain a homogeneous vapor-gas mixture and avoid steam condensation, the supplied nitrogen gas, passing through the heat exchanger 4, is heated to a temperature corresponding to the temperature of the steam in line 2 of the steam curtain or exceeding it. Direct preparation of a homogeneous vapor-gas mixture is carried out in a gas mixer 5. In this case, the gas mixer 5 has a design based on the Venturi effect. As a heating medium, in particular a coolant, the heat exchanger 4 can use live steam obtained in the boiler room for the technical needs of the enterprise or wet saturated steam, additionally heated in the coils of the technological furnace before it is extinguished. The intensity of the supply of coolant steam is adjusted automatically by valve 14 through the controller 17 for controlling the operation of the steam curtain and depends on the parameters in line 2 of the steam supply. If the enterprise does not have the opportunity to use steam as a coolant, heating of nitrogen gas can be carried out in an electrically heated heat exchanger (Fig. 2).

Thus, the homogeneous vapor-gas mixture obtained in the gas mixer 5 flows through the connecting pipeline 6 through the tee-distributor 7 into the manifold 1 to form a vapor-gas curtain around the perimeter of the technological furnace. In this case, the steam-gas jets emitted from the manifold holes are directed vertically upward and form a dense protective curtain that prevents explosive mixtures from entering the burners of the technological furnace.

The technical result achieved by the group invention is to increase the efficiency and improve steam curtains by obtaining a homogeneous steam-gas mixture capable of creating a dense protective curtain around the perimeter of technological furnaces.

The technical and economic efficiency of using inventions united by a single inventive concept is due to the following advantages.

1. Significant reduction of damage in the event of emergency situations by eliminating the entry of explosive gas-air mixtures into the burners of technological furnaces.

2. Increasing the reliability and efficiency of steam curtains in the event of a lack of steam in the steam lines, through the additional use of gases, such as nitrogen, and, as a result, obtaining dense steam-gas jets in the curtains.

3. The possibility of technical reconstruction of existing steam curtains by introducing additional equipment into existing technological schemes.

4. Reducing the time of operational actions to turn on steam curtains by automating the turn-on and control processes of shut-off and control valves.

Claims (5)

1. A method of fire protection of technological furnaces, including creating a protective curtain of a technological furnace by supplying a fire extinguishing agent to a horizontal perforated manifold of the outer protective curtain of the furnace, characterized in that a mixture of water vapor and nitrogen is used as a fire extinguishing agent, while creating a vapor-gas curtain, and in the curtain collector supplies a homogeneous vapor-gas mixture, the preparation of which is carried out in a gas mixer with the Venturi effect, while in order to avoid condensation of water vapor and obtain a homogeneous vapor-gas mixture, nitrogen is preheated in a heat exchanger to a temperature corresponding to the temperature of water vapor, and the parameters of the resulting vapor-gas mixture are regulated and The operation of the protective steam-gas curtain is controlled automatically by a control controller. 2. The method of fire protection of technological furnaces according to claim 1, characterized in that the thermal energy necessary for the operation of the heat exchanger and heating of nitrogen is taken from the technological furnaces, or the steam boiler room of the enterprise, or is obtained through the use of electric heat exchangers. 3. A fire protection device for technological furnaces, intended for implementing the method according to claim 1, containing a horizontal perforated manifold of the outer protective curtain of the technological furnace, pipelines for supplying a fire extinguishing agent to the manifold, shut-off and control valves, devices for monitoring the operating parameters of the protective curtain, characterized in that that the device is designed to use water steam, as well as a mixture of steam and nitrogen as a fire extinguishing agent, wherein the device contains a steam supply line to a protective curtain with a measuring sensor-flow meter, and a nitrogen supply line in which a heat exchanger is installed, both lines are combined a gas mixer with the Venturi effect, wherein said gas mixer is connected by a pipeline to the collector of the protective curtain and the gas pipeline is connected to a heat exchanger installed in the nitrogen supply line, designed to heat the nitrogen to a temperature corresponding to the temperature of water vapor to eliminate condensation of water vapor and obtain a homogeneous vapor-gas mixture in the gas mixer, and the shut-off and control valves installed in the indicated lines, controlled by an electric motor, a heat exchanger and a measuring sensor-flow meter, designed to determine the temperature and actual steam supply, are electrically connected to a software and hardware complex - a controller for automatically controlling the operation of the protective curtain . 4. The fire protection device for technological furnaces according to claim 3, characterized in that it contains a steam-coolant supply line connected to a heat exchanger and equipped with valves installed in it, controlled by electric motors and electrically connected to the controller. 5. Fire protection device for technological furnaces according to claim 3, characterized in that the heat exchanger in the nitrogen supply line is electric.